It is now generally recognized in the computer software industry that multi-tier distributed server architectures confer a variety of benefits, including increased capacity, throughput, fault tolerance, scalability, and reliability. However, due to their decentralized nature, such architectures pose particular difficulties in the area of application management and administration.
One of the chief difficulties involved with such systems is their cost of ownership. When deployed in production settings, software systems based on distributed server architectures typically incur a high cost of ownership, including costs incurred from the need to employ and train a large number of administrative and maintenance personnel as well as costs incurred from the difficulty of isolating and fixing problems. Cost of ownership is further multiplied in the case of software systems that are distributed across multiple geographic locations.
This high cost of ownership constrains the market for commercial software products based on distributed server architectures. Minimizing the cost of ownership significantly expands the potential market for these software products and allows more organizations to take advantage of the benefits conferred by such products.
A special type of software program is a background process that may be started automatically by an operating system at startup. For example, background processes that run on certain Microsoft operating systems such as Windows NT and Windows 2000 are termed “services.” Generally, services are a background process which is loaded by part of the operating system kernel, typically at startup or bootup, prior to any user log-ins. Services differ from other software programs in that they can be configured to start automatically when the operating system starts, thus simplifying administration. In addition; they generally do not require a logged-on user in order to run and they run in their own security context. Services typically are accessed by an operating system directly, and thus have no local user interface, although they can usually be launched manually by a user through a service control utility, e.g., a “control panel” or the like. Other operating systems, such as UNIX, have similar background processes, typically termed daemons, although for purposes of the present invention these background processes may be referred to as generally as services.
A software system based on distributed services, i.e., services existing on various remote computers, can take advantage of the characteristics of services to reduce the cost of ownership. However, because services have no local user interface; such a software system typically requires a remote administrative user interface to manage the distributed services. It would be desirable to enable the administration of such a software system either from a single computer at a central location or from multiple computers at different locations, depending on the deployment scenario and the requirements of the customer.
Existing network management standards, such as the SNMP and CMIP standards, have focused on management of the underlying network and associated devices rather than management of heterogeneous networked software applications. SNMP, for example, supports getting and setting properties on user-definable managed objects but offers no direct support for parameterized method execution. Other management standards, such as WBEM, can accommodate services as managed objects, but the relevant provided interfaces are limited to the least common subset of service properties and methods and are not easily extensible to accommodate rich service-specific property sets.
While certain existing network management approaches can theoretically support rich service-specific property sets through the definition of custom classes or interfaces, such approaches generally suffer from one or more of the following limitations: There is typically no easy-to-use programming interface to support rapid application development the design and implementation of custom classes and interfaces is prohibitively difficult and labor-intensive, property sets are at best expressible simply as collections of name/value pairs and therefore cannot easily express rich structure, property sets are generally limited in size, custom classes and interfaces are generally not resilient to change in the underlying service property sets no mechanism is provided to control bandwidth by allowing a client administrative program to specify a subset of properties to retrieve, and/or no security mechanism is provided.
In some networked applications of the prior art, e.g. a front-end database management application, an application may communicate directly with managed network services. However, there are problems with such a design. For example, this design prohibits any viewing and setting of configuration information unless the managed services are active. This reliance on services being active is unacceptable, because typically services are heavyweight processes that often taken a long time to initialize and consume many system resources. In a distributed application it is not uncommon for the services on a particular remote machine to be inactive, which in such a design would prohibit the application of consistent configuration changes across similar services on several machines.
Generally, service properties and statistics are hierarchical and nontabular in structure and generally lack fixed dimensionality. Because the set of properties and statistics desired in network management communications, regarding both background process status and network performance parameters, are likely to change frequently in the future, preferably the design of a network management tool must be flexible and extensible. In addition, various data types pertinent to network administration and performance analysis must be supported, including strings, Boolean or dummy variables, date/time, and integrals. Incurring a network round trip for each read or write of an individual property or statistic is undesirable, because this may cause networked application administration to impose a significant load on the network. Similarly, it is desirable to be able to apply changes to service properties in bulk or batched fashion. Finally, it would be desirable that collections of properties and statistics should be accessible and navigable using a standardized or open technique rather than a proprietary one if possible.
It would be desirable to provide a software tool for management of distributed services on a network, providing for ease of administration for distributed computer applications that run on computer network systems with reduced cost of ownership, that does not suffer from the above limitations. In particular, in managing distributed services on a computer network, rather than being limited to getting and setting one property or statistic at a time, preferably a software tool would act in a fashion to batch certain functions in order to conserve bandwidth when possible. Preferably, this software tool will combine relative ease of client programming with extensibility, while minimizing network overhead and traffic.
It is at least theoretically possible to provide distributed computer applications administration tools utilizing COM interface properties, tabular reports, standard COM collection objects such as SAFEARRAYs, or custom marshalling. However, these potential methods violate the desired administration properties detailed above.
An Extensible Markup Language (XML, for eXtensible Markup Language) has been developed as a restricted form of the more cumbersome SGML (Standard Generalized Markup Language). Generally, XML describes a class of data objects, XML documents, which may be parsed by XML processors in remote locations in order that the remote application may access the structure and content of the XML document in a form meaningful to the application. The XML processor, following the XML rules about what information from the XML document it must provide to the application, sends relevant data and instructions to the remote application. In contrast to HTML, a different SGML derivative, XML provides a facility for developers to provide their own XML markup and tag types which may be useful in providing information to a remote application. This application, via a XML processor, may receive instructions or data contained in an XML document, and may return data or instructions in a similar way. While XML documents will naturally be larger than application-specific or native binary files sent directly between applications, they are language independent, and as text files, are easier to maintain and debug than corresponding binary “bitstream” transmissions.